Smart move by Facebook to settle early. This could have been a disaster if it was allowed to proceed. Facebook treads on very thin ice with some privacy laws. A very high risk company.
I think sed pretty much displaced ed. I still use ed but sed offers the same functionality and it's easier to script. One exception is the j command for joining lines.
For better or worse, in some of today's base Linux distributions, you might find ed missing. You will almost always find sed though.